Footballer Diego Maradona famously juggled a golf ball on his foot during his stint while former footballer-turned-presenter Gary Lineker debated the motion "this house would rather participate than commentate".

Barry White lent his weight to the union last year

Acquitted American football star OJ Simpson also braved the 900 or so students who pack the chamber for the main debates.

Last year Barry White was invited to address the union as "the world's most romantic singer-songwriter", and spoke of his worries about music on the internet.

This term's guests have included quiz show presenter Nicholas Parsons, footballer Gareth Southgate and actress Helen Baxendale, and Michael Jackson's appearance is followed on Wednesday by the founder of the Orange telecommunications company, Hans Snook.

While not part of the university itself, the Oxford Union also provides social facilities for the city's thousands of students, who would otherwise be split across its forty separate colleges.

It also boasts the city's only late-night student bar - thanks to the efforts of former deputy prime minister Michael Heseltine, an officer of the union in the 1950s.